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Biomedical subjects

M Tsuzuki

Publications and source records attributed to M Tsuzuki.

At least 109 records · Page 6Linked to original sources
PubMed1984

Susceptibility of hepatitis B virus to disinfectants or heat.

Using direct chimpanzee inoculation as an assay method, we tested the abilities of the following chemical or physical treatments to inactivate hepatitis B virus in human plasma: 1% aqueous glutaraldehyde at 24 degrees C for 5 min, 0.1% aqueous glutaraldehyde at 24 degrees C for 5 min, 80% ethyl alcohol at 11 degrees C for 2 min, and heat at 98 degrees C for 2 min. All treatments were shown to be effective, indicating that the resistance level of the hepatitis B virus is not extreme.

Aldehydes↗
PubMed1984

[Brighton epistaxis balloon: application for cranio-facial injury].

Head injury patients often complicate facial and/or multiple injuries other than cranio-cerebral insults and perplex the emergency staffs. The authors used Brighton epistaxis balloon for such patients with massive nasal bleeding and reported the utility of the balloon not only in such state of emergency but also for a few days to control the hemorrhage mostly caused by craniobasal fractures or rupture of the adjacent vessels. One hundred and twenty-nine patients were transported and hospitalized in Department of Emergency Medicine, University of Tokyo Hospital, Tokyo, Japan during the period from October, 1981 to January, 1983. Nasal bleeding was noted in 29 cases of them and the balloon was used in 10 cases, who were from 19 to 76 years of age, all males and suffered from basal fractures or craniofacial injuries. Six cases of them were also accompanied with fractures in the extremities or pelvis, hemopneumothorax and/or intra-abdominal bleeding and could not but put on "Military anti-shock trousers" for the management of hypovolemic shock, hence the nasal bleeding should be managed immediately in the emergency room. In these situations the balloon was inserted into both nasal cavities in all the patients, to control successfully the nasal hemorrhages one of which contaminated cerebrospinal fluid and three of which were sure to be pulsatile due to arterial injury. The Brighton epistaxis balloon is to be removed within twelve or twenty-four hours, but in the authors' cases the mean duration for the hemostasis was 58.9 hours for 6 survivors and 49.6 hours for all 10 cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Isolation and characterization of a 4-O-methylglucuronic acid-containing glycosphingolipid from spermatozoa of a fresh water bivalve, Hyriopsis schlegelii.

A novel glycosphingolipid, provisionally named Lipid IV (Hori, T., Sugita, M., Ando, S., Kuwahara, M., Kumauchi, K., Sugie, E., and Itasaka, O. (1981) J. Biol. Chem. 256, 10979-10985), was obtained from spermatozoa of the fresh water bivalve, Hyriopsis schlegelii. The yield of the glycolipid was 2.2 mg/g of dried spermatozoa. The structure of the glycolipid was elucidated by partial hydrolysis, permethylation analysis, and proton nuclear magnetic resonance. The following structure is proposed: GlcA4Me beta 1-4(GalNAc3Me alpha 1-3)Fuc alpha 1-4GlcNAc beta 1-2Man alpha 1-3(Xyl beta 1-2)Man beta 1-4Glc beta 1-Cer. The acidic glycolipid is unique in containing 4-O-methylglucuronic acid as well as an internally located fucose. Palmitic acid, stearic acid, and C18-sphingosine are the major aliphatic components. This composition is similar to those of other neutral spermatozoan glycolipids, Lipid I (Hori, T., Sugita, M., Kanbayashi, J., and Itasaka, O. (1977) J. Biochem. (Tokyo) 81, 107-114) and Lipid II (Hori, T., Takeda, H., Sugita, M., and Itasaka, O. (1977) J. Biochem. (Tokyo) 82, 1281-1285), suggesting a possible metabolic relationship among them.

Acidic Glycosphingolipids↗
PubMed1983

A case of 17 alpha-hydroxylase deficiency with special reference to the renal kallikrein-kinin system.

In a 26-year-old male with 17 alpha-hydroxylase deficiency, endocrinological examinations were performed not only after, but also before the onset of clinical signs and symptoms. In addition, the pathophysiological role of the renal kallikrein-kinin system was investigated in this patient. In spite of the fact that this disease is congenital, in the mechanism of its onset, this patient had a period of endocrinological normality before onset; that is, 9 months before onset, both ACTH and cortisol were within the normal range, although the former would be significantly higher and the latter significantly lower than normal values after the onset. In this case, both urinary kallikrein and kininase excretions abnormally increased and then returned to normal after dexamethasone treatment.

Adrenal Cortex Hormones↗
PubMed1983

[Some practical problems of clinical diagnosis of brain death].

The authors experienced thirty brain deaths including eighteen head injuries and seven cerebrovascular accidents during the period from Nov. 1980 to Dec. 1982 and encountered with some practical problems on clinical diagnosis of brain death. In sixteen patients subjected to barbiturate (pentobarbital) therapy, the attempt to meet the criteria of brain death made it necessary to confirm the total cerebrocirculatory arrest as well as to measure the serum concentration of pentobarbital and assure its level low enough. But as a result of the angiograms performed in twenty-four cases the cerebral angiography sometimes failed to give sufficient evidence to confirm it not merely because of the angiographical intracranial delayed opacification but also because of the dissociation of filling between supra- and infratentorial spaces or between right and left hemispheres. And besides the contrast enhancement of cerebral vessels was verified in computed tomograms of two cases among ten cases who had already met the criteria and demonstrated angiographical nonfilling phenomenon. The angiographical narrowing of C 1-2, A 1, M 1 portions or basilar artery observed on serial angiograms preceding the angiographical nonfilling phenomenon was regarded as direct vascular compression by cerebral swelling or vasospasm and considered to suggest that brain death might be impending. At present the continuous monitoring of intracranial pressure performed in twenty-six cases proved to be a convincing guide to suspicion of brain death or impending brain death according to decrease in cerebral perfusion pressure and appearance of so-called plateau waves recorded in four cases.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1982

Determination of NAD Malic Enzyme in Leaves of C(4) Plants : EFFECTS OF MALATE DEHYDROGENASE AND OTHER FACTORS.

Malate dehydrogenase may interfere with the assay of NAD malic enzyme, as NADH is formed during the conversion of malate to oxaloacetate. During the present study, two additional effects of malate dehydrogenase were investigated; they are evident only if the malate dehydrogenase reaction is allowed to reach equilibrium prior to initiating the malic enzyme reaction. One of these (Outlaw, Manchester 1980 Plant Physiol 65: 1136-1138) might cause an underestimation of NAD reduction by malic enzyme due to the oxidation of NADH during reversal of the malate dehydrogenase reaction. A second effect may result in overestimation of malic enzyme activity, as Mn(2+)-catalyzed oxaloacetate decarboxylation causes continuing net NADH formation via malate dehydrogenase. These effects were studied by assaying the activity of a partially purified preparation of Amaranthus retroflexus NAD malic enzyme in the presence or absence of purified NAD malate dehydrogenase.A model was developed which allowed the generation of theoretical curves describing the influence of malate dehydrogenase on the assay of malic enzyme activity. The experimental data obtained agreed closely with these curves. The conditions included 5 millimolar malate, 2 millimolar NAD, and 4 millimolar Mn(2+) (pH 7.2 to 7.8 at 30 degrees C). At low activities of malic enzyme (1 nanomole per minute per milliliter or less), the presence of malate dehydrogenase leads to a substantial overestimation of malic enzyme activity due to the Mn(2+)-catalyzed decarboxylation of oxaloacetate having a dominant effect. When the level of malic enzyme is greater than 1 nanomole per minute per milliliter, reversal of malate dehydrogenase has a dominant transient effect, causing a lag of up to several minutes, after which the change in absorbance reflects the true rate of malic enzyme. Independent of this effect is a lag in the activator-dependent rate, which could be eliminated by preincubating the enzyme with activator (coenzyme A).An assay procedure designed to minimize the influence of these effects is described. New data are presented on the activity of NAD malic enzyme in leaves of different subgroups of C(4) plants.

Journal Article↗
PubMed1982

Influence of Nitrate and Ammonia on Photosynthetic Characteristics and Leaf Anatomy of Moricandia arvensis.

The leaf anatomy and certain photosynthetic properties of nitrate- and ammonia-grown plants of Moricandia arvensis (L.) DC., a species previously reported to be a C(3)-C(4) intermediate, were investigated. Nitrate-grown plants had a high level of malate in the leaves while ammonia-grown plants had low levels of malate. In young leaves of nitrate-grown plants, there was a diurnal fluctuation of malate content, increasing during the day and decreasing during the night. Titratable acidity remained low in leaves of both nitrate- and ammonia-grown plants.In nitrate-grown plants, the activity of phosphoenolpyruvate (PEP) carboxylase was about 2-fold higher than in ammonia-grown plants, the latter having activity typical of C(3) species. Also, in nitrate-grown plants, the ratio of activities of ribulose 1,5-bisphosphate (RuBP) carboxylase/PEP carboxylase was lower than in ammonia-grown plants. Nitrate reductase activities were higher in nitrate- than in ammonia-grown plants and the greatest activity was found in younger leaves.With nitrate-grown plants, during a pulse-chase experiment the label in malate, as a percentage of the total labeled products, increased from about 7% after a 10-second pulse with (14)CO(2) up to 17% during a 5-minute chase with (12)CO(2). The pattern of (14)C labeling in various metabolites suggests the primary carboxylation is through RuBP carboxylase with a secondary carboxylation through PEP carboxylase. In similar experiments, with ammonia-grown plants, the percentage label in malate was only 0% to 4% with no increase in malate labeling during the chase period. The CO(2) compensation point was lower in nitrate-grown than ammonia-grown plants.There was no evidence of Kranz-like anatomy in either the nitrate or ammonia-grown plants. Mitochondria of bundle-sheath cells were strikingly positioned along the inner tangential wall. This might allow the chloroplasts of these cells to fix the mitochondrial photorespired CO(2) more effectively and contribute to the low CO(2) compensation point in the species. Chloroplasts of bundle-sheath cells and contiguous mesophyll cells were similar in size and structure in plants grown on different media, although chloroplast thylakoids and stromata of the ammonia-grown plants stained more intensely than those of nitrate-grown plants. In addition, irregular clusters of phytoferritin particles occurred in the chloroplasts of the ammonia-grown plants.The results indicate that the substantial activity of PEP carboxylase, incorporation of CO(2) into malate, the high malate content, and in part the relatively low CO(2) compensation point in Moricandia arvensis may be accounted for by metabolism of nitrate rather than by a state of C(3)-C(4) intermediacy.

Journal Article↗
PubMed1982

Hemodynamic and natriuretic responses to intravenous infusion of dopamine in patients with essential hypertension.

In order to clarify the role of dopamine on the pathophysiology of essential hypertension, mean arterial pressure (MAP), heart rate (HR), urine volume (UV), urinary sodium excretion (UNaV), endogenous creatinine clearance (Ccr), fractional excretions of sodium (FENa), inorganic phosphorus (FEP) and potassium (FEK), plasma renin activity (PRA), plasma aldosterone concentration (PAC) and plasma noradrenaline concentration (PNA) were measured before and after intravenous infusion of dopamine (3 micrograms/kg/min, 60 min) in normotensive (NT) and essential hypertensive subjects (EHT). Following dopamine infusion, a significant decrease of MAP and an increase of HR were observed in EHT but not in NT. UV, UNaV, Ccr, FENa, FEP and FEK increased significantly in both NT and EHT, and changes in these except for Ccr were significantly greater in EHT than in NT. In EHT, following dopamine infusion, PNA was clearly elevated, but no remarkable change was found in PRA and PAC. A significantly positive correlation was found between delta UNaV and delta FENa or delta FEP, and between delta FENa and delta FEP, while no significant relation was observed between delta UNaV and delta Ccr, delta MAP or MAP before dopamine infusion. A significant inverse correlation between supine PRA before dopamine infusion and delta FENa or delta FEP and a positive correlation between age and delta FENa or delta FEP were also observed in these patients. The changes in UNaV positively correlated with delta FENa and delta FEP in both low renin (group L) and normal renin EHT (group N) and with delta Ccr i group N but not in group L. The mean values of delta FENa, delta FEP and delta FEK were significantly higher in group L as compared with those in age-matched group N. These results suggest that, since the enhanced response to infused dopamine may reflect reduced dopaminergic activity, attenuation of renal dopaminergic activity might exist and be involved through a distribution of water-sodium metabolism, at least in part, in the pathophysiological mechanism in EHT, particularly in group L.

Adult↗